Human embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of preimplantation embryos (1). Similar to mouse ES cells, they can be expanded to large numbers while maintaining their potential to differentiate into various somatic cell types of all three germ layers (1-4). The in vitro differentiation of ES cells provides new perspectives for studying the cellular and molecular mechanisms of early development and the generation of donor cells for transplantation therapies. Indeed, mouse ES cells have been found to differentiate in vitro to many clinically relevant cell types, including hematopoietic cells (5), cardiomyocytes (6), insulin-secreting cells (7), and neurons and glia (8-11). Following transplantation into the rodent central nervous system (CNS), ES cell-derived neural precursors have been shown to integrate into the host tissue and, in some cases, yield functional improvement (13). A clinical application of human ES cells would require the generation of highly purified donor cells for specific tissues and organs.
Needed in the art is a simple, yet efficient, strategy for the isolation of transplantable neural precursors from differentiating human ES cell cultures.